Near-infrared absorbing fine particle dispersion liquid, near-infrared absorbing fine particle dispersion body, near-infrared absorbing transparent substrate, near-infrared absorbing laminated transparent substrate

Abstract

There is provided a near-infrared absorbing fine particle dispersion liquid containing near-infrared absorbing fine particles, thereby as well as exhibiting near-infrared light absorption properties and suppressing a scorching sensation on the skin when used in structures such as window materials and the like, also enabling usage of communication devices, imaging devices, sensors and the like that employ near-infrared light through these structures, a near-infrared absorbing film or a near-infrared absorbing glass, a dispersion body or a laminated transparent substrate, the dispersion liquid containing at least composite tungsten oxide fine particles and antimony doped tin oxide fine particles and/or tin doped indium oxide fine particles as near-infrared absorbing fine particles, wherein in the composite tungsten oxide fine particles, an average value of a transmittance in a wavelength range of 800 to 900 nm is 30% or more and 60% or less, and an average value of a transmittance in a wavelength range of 1200 to 1500 nm is 20% or less, and a transmittance at a wavelength of 2100 nm is 22% or less, when a visible light transmittance is 85% at the time of calculating only light absorption by the composite tungsten oxide fine particles, and containing mixed particles of the composite tungsten oxide fine particles and antimony-doped tin oxide fine particles and/or tin-doped indium oxide fine particles dispersed in a liquid medium, wherein the liquid medium is selected from rater, an organic solvent, an oil and fat, a liquid resin, a liquid plasticizer for plastics, or a mixture thereof, wherein when a visible light transmittance is adjusted to 85% at the time of calculating only light absorption by the near-infrared absorbing fine particles in the dispersion liquid by diluting with the liquid medium, an average value of a transmittance in the wavelength range of 800 to 900 nm is 30% or more and 60% or less, an average value of a transmittance in the wavelength range of 1200 to 1500 nm is 20% or less, and a transmittance at the wavelength of 2100 nm is 11% or less.

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